1
|
Lian Q, Gao Y, Li Q, He X, Jiang X, Pu Z, Xu G. Cereblon Promotes the Ubiquitination and Proteasomal Degradation of Interleukin Enhancer-Binding Factor 2. Protein J 2020; 39:411-421. [PMID: 33009960 DOI: 10.1007/s10930-020-09918-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2020] [Indexed: 11/25/2022]
Abstract
Interleukin enhancer-binding factor 2 (ILF2) forms a heterodimer with interleukin enhancer-binding factor 3 (ILF3) via double-stranded RNA-binding motif and zinc finger associated domain and thus regulates gene expression and cancer cell growth. However, how ILF2 is degraded in cells remains elusive. In this work, using stable isotope labeling by amino acids in cell culture (SILAC) quantitative proteomics, we find that ILF2 is downregulated in cells expressing cereblon (CRBN). Using affinity purification and immunoblotting analysis, we demonstrate that CRBN interacts with ILF2 and functions as a substrate receptor of the cullin-4 RING E3 ligase complex. Biochemical experiments disclose that CRBN expression reduces ILF2 protein level and this reduction is diminished when the proteasome is inhibited. Upon protein synthesis inhibition, the degradation of ILF2 is enhanced by CRBN. Moreover, CRBN promotes the ubiquitination of ILF2 and thus results in the ubiquitin-mediated proteasomal degradation. Analyses of previously identified post-translational modification sites and the crystal structure of ILF2 discover the potential ubiquitination sites on ILF2. Through mutagenesis and biochemical experiments, we further reveal that the K45R mutation completely abolishes the effect of CRBN on ILF2, suggesting that this is the key residue responsible for its ubiquitination. Taken together, we identify an E3 ligase that regulates ILF2 and uncover a molecular pathway for its degradation. This work might be helpful to elucidate the molecular mechanism by which CRBN regulates diverse cellular functions.
Collapse
Affiliation(s)
- Qihui Lian
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, China
| | - Yuan Gao
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, China
| | - Qian Li
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, China
| | - Xian He
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, China
| | - Xiaogang Jiang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, China
| | - Zhongjian Pu
- Department of Oncology, Haian Hospital of Traditional Chinese Medicine, Haian, 226600, Jiangsu, China.
| | - Guoqiang Xu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, China.
| |
Collapse
|
2
|
Xu Q, Hou YX, Langlais P, Erickson P, Zhu J, Shi CX, Luo M, Zhu Y, Xu Y, Mandarino LJ, Stewart K, Chang XB. Expression of the cereblon binding protein argonaute 2 plays an important role for multiple myeloma cell growth and survival. BMC Cancer 2016; 16:297. [PMID: 27142104 PMCID: PMC4855823 DOI: 10.1186/s12885-016-2331-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 04/29/2016] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Immunomodulatory drugs (IMiDs), such as lenalidomide, are therapeutically active compounds that bind and modulate the E3 ubiquitin ligase substrate recruiter cereblon, thereby affect steady-state levels of cereblon and cereblon binding partners, such as ikaros and aiolos, and induce many cellular responses, including cytotoxicity to multiple myeloma (MM) cells. Nevertheless, it takes many days for MM cells to die after IMiD induced depletion of ikaros and aiolos and thus we searched for other cereblon binding partners that participate in IMiD cytotoxicity. METHODS Cereblon binding partners were identified from a MM cell line expressing histidine-tagged cereblon by pulling down cereblon and its binding partners and verified by co-immunoprecipitation. IMiD effects were determined by western blot analysis, cell viability assay, microRNA array and apoptosis analysis. RESULTS We identified argonaute 2 (AGO2) as a cereblon binding partner and found that the steady-state levels of AGO2 were regulated by cereblon. Upon treatment of IMiD-sensitive MM cells with lenalidomide, the steady-state levels of cereblon were significantly increased, whereas levels of AGO2 were significantly decreased. It has been reported that AGO2 plays a pivotal role in microRNA maturation and function. Interestingly, upon treatment of MM cells with lenalidomide, the steady-state levels of microRNAs were significantly altered. In addition, silencing of AGO2 in MM cells, regardless of sensitivity to IMiDs, significantly decreased the levels of AGO2 and microRNAs and massively induced cell death. CONCLUSION These results support the notion that the cereblon binding partner AGO2 plays an important role in regulating MM cell growth and survival and AGO2 could be considered as a novel drug target for overcoming IMiD resistance in MM cells.
Collapse
Affiliation(s)
- Qinqin Xu
- Department of Biochemistry & Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic Arizona, 13400 E. Shea Boulevard, Scottsdale, AZ, 85259, USA.,Zhejiang Provincial Key Laboratory of Nephrology, Hangzhou Traditional Chinese Medical Hospital, 453 Tiyuchang Rd, Hangzhou, 310007, China
| | - Yue-xian Hou
- Department of Biochemistry & Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic Arizona, 13400 E. Shea Boulevard, Scottsdale, AZ, 85259, USA
| | - Paul Langlais
- Department of Biochemistry & Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic Arizona, 13400 E. Shea Boulevard, Scottsdale, AZ, 85259, USA
| | - Patrick Erickson
- Department of Biochemistry & Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic Arizona, 13400 E. Shea Boulevard, Scottsdale, AZ, 85259, USA
| | - James Zhu
- Department of Biochemistry & Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic Arizona, 13400 E. Shea Boulevard, Scottsdale, AZ, 85259, USA
| | - Chang-Xin Shi
- Division of Hematology-Oncology, Mayo Clinic Arizona, Scottsdale, AZ, USA
| | - Moulun Luo
- Center for Metabolic and Vascular Biology, Arizona State University, Tempe, AZ, USA
| | - Yuanxiao Zhu
- Division of Hematology-Oncology, Mayo Clinic Arizona, Scottsdale, AZ, USA
| | - Ye Xu
- Department of Biochemistry & Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic Arizona, 13400 E. Shea Boulevard, Scottsdale, AZ, 85259, USA.,Key Laboratory of Carcinogenesis and Translational Research, Breast Center, Beijing Cancer Hospital & Institute, Peking University Cancer Hospital, Beijing, 100142, P. R. China
| | - Lawrence J Mandarino
- Center for Metabolic and Vascular Biology, Arizona State University, Tempe, AZ, USA.,Department of Medicine, Mayo Clinic Arizona, Scottsdale, AZ, USA
| | - Keith Stewart
- Division of Hematology-Oncology, Mayo Clinic Arizona, Scottsdale, AZ, USA
| | - Xiu-bao Chang
- Department of Biochemistry & Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic Arizona, 13400 E. Shea Boulevard, Scottsdale, AZ, 85259, USA.
| |
Collapse
|